System and method for drilling multilateral wells using magnetic ranging while drilling

Abstract

Systems and methods for drilling a multilateral well using magnetic ranging while drilling are provided. In accordance with one embodiment, a method of drilling a multilateral well includes drilling and casing a mother wellbore, installing a multilateral junction, drilling and casing a first lateral well from the multilateral junction, and drilling a second lateral well from the multilateral junction using magnetic ranging while drilling such that the second lateral well has a controlled relationship relative to the first lateral well. The first and second lateral wells may form a SAGD well pair, in which case the first lateral well may be a producer well and the second lateral well may be an injector well.

What is claimed is: 
     
       1. A method for drilling a multilateral well comprising:
 drilling and casing a mother wellbore in a subsurface formation; 
 installing a multilateral junction in the mother wellbore; 
 drilling and casing a first lateral well from the multilateral junction such that the first lateral well includes a liner; 
 drilling a second lateral well from the multilateral junction, using a bottom hole assembly having a drill bit, an electric current driving tool, and a magnetometer; and 
 wherein drilling the second lateral well includes (i) causing the electric current driving tool to provide an electrical current that travels through the subsurface formation to the first lateral well and along the liner such that the current traveling along the liner creates a magnetic field, (ii) causing the magnetometer to measure the magnetic field, and (iii) magnetically ranging while drilling the second lateral well in a controlled relationship to the first lateral well using the magnetometer measurement. 
 
     
     
       2. The method of  claim 1 , wherein the controlled relationship between the first and second lateral wells is an approximately constant distance and spatial relationship. 
     
     
       3. The method of  claim 2 , wherein the separation distance of the second lateral well relative to the first lateral well varies by less than or equal to 20% along a length of the second lateral well. 
     
     
       4. The method of  claim 1 , wherein said drilling the second lateral well is accomplished such that the second lateral well is directly above the first lateral well. 
     
     
       5. A method of drilling a multilateral well comprising:
 drilling and casing a mother wellbore in a subsurface formation; 
 installing a multilateral junction in the mother wellbore; 
 drilling and casing a first lateral well from the multilateral junction, wherein the first lateral well includes a liner and has a length of at least 500 meters; 
 drilling a second lateral well from the multilateral junction using a bottom hole assembly having a drill bit, an electric current driving tool, and a magnetometer, wherein drilling the second lateral well comprises maintaining a separation distance from the first lateral well having a variance of no greater than two meters over a length of at least 500 meters; and 
 wherein drilling the second lateral well includes (i) causing the electric current driving tool to provide an electrical current that travels through the subsurface formation to the first lateral well and along the liner such that the current traveling along the liner creates a magnetic field, (ii) causing the magnetometer to measure the magnetic field, and (iii) magnetically ranging while drilling the second lateral well so as to maintain the separation distance using the magnetometer measurement. 
 
     
     
       6. The method of  claim 5 , wherein drilling and casing the first lateral well comprises drilling and casing a producer well, and wherein drilling the second lateral well comprises drilling an injector well; and
 wherein the method further comprises installing a steam generator in the injector well.